Betting all the chips on Wickerman only worked temporarily though didn't it? And they virtually had to give away season passes to get people to come and ride it. Whilst Wickerman was undoubtedly an excellent investment, filled a hole in the lineup, and is well themed, the neglect of the rest of the place continued.
Aside from the 3 desperately needed new flat rides, they've had to divert masses of Capex just to try and stand still. This has come late in the day, and is why we've ended up with this season and the last being so lackluster. Something had to be done about Duel, The Skyride, Hex, and the PLC for Spinball. It seems like the to-do list was so long that it came too late for the Spa and Enterprise. Although Wickerman was desperately needed, it seems so were all these other things and Capex is finite.
Now, Galactica needs work, the Smiler has been looking visually bad for a number of years, and the rapids is pretty baron these days. There's aging hardware like Oblivion, RMT, and the Monorail that could need some serious attention soon. That's before we talk about all the peeling paint, empty buildings, awful permanent food offering, and needed Dungeon replacement. Horizon is expensive, and the costs of everything they're investing in at the moment, and need to invest in soon, has to come from somewhere.
It's likely that we can't have both, otherwise we end up in a situation like we're in now. The ride lineup has been embarrassing these last 2 seasons due to years of underinvestment. We spent 3 seasons with funfair flats drafted in. I'm sure Horizon would be wonderful and would attract a large number of guests in it's opening year, but what would the rest of the park be like by then? If they started work on Horizon soon, I bet you'd be looking at significant trade-offs elsewhere.